Stiffening material



Jan. 14, 1936. R. HAMILTON 2,027,973

STIFFENING MATERIAL Filed Aug. 19, 1933 v lNvEN-TOR .'.RUSBSELL HAMILTON f1/1.4 ATTORNEY Vintenten .1m14.193s i e 2,027,973 y UNITED jsTATEsfPATENT oFFiCE missen.Hamilton Bloomfield, N. J., assigner to,

The Celastic Corporation, Wilmington, Del., a corporation of Delawaref f Applicationaugast 19,. 193s, serial No. 685,911

s claims, (c1. 12I14s l, This invention relates to methods of preparing character indicated, my invention consists in stiiening material, and particularly to methods the various matters hereinafter described and of preparing an improved stiffening material .of claimed. -the general type/disclosed in U. S. Patent 1,1256,- These objects are accomplished by impreg- 240, Lovell, February 12, 1918.' Although not rehating the fabric with a solution of colloid and stricted to such use, material of the present type introducing the undried, impregnated-'fabricv into finds advantageousapplication as stiiening maa precipitating bath, the colloid solution having terial for boots and shoes, such as fabric, patent present therein a restraining agent acting to leather, cut-out, or perforated boots and shoes, prevent complete precipitation of the colloidal and therefore is described with more particular y matter during treatment of the fabric in the 10 reference to the boot and shoe industry. precipitating bath. The result is that when the Material of the Lovell type comprises a base material is dried, e. g. air dried, although much fabric such as a woveny material, for example of the colloidal material is inprecipitated form. cotton cloth, or a structureless material, for there is also a certain amount that is in a harder 1'5v example felt or paper, with its interstices carryor more colloided form. As. the colloidal matter' 15 'ing precipitated colloidal material in a highly in the fabric is not -entirely in a precipitated orporous form termed powdered by Lovell, suchV highly porous condition, it does not absorb the `as, a cellulosic derivative, casein, albumin and solvent with which the stiffening maternal is various gum and resins. In use, the fabric is ultimately treated for use in the lasting operaimmersed in a solvent for the precipitated mation, as quickly or in such a large amount as 20 terialjfthereby to resolve the same into a cowould the ordinary stffenng material 60111391111- alescent i'laccid condition, and when the material ing only precipitated colloidal material, and, is in this condition the fabric is applied in the therefore, does not become as mushy as would lastingoperations, shapedand allowed to hardthe ordinary material. Yet, on the other hand en, by evaporation of solvent, in its shaped conit will absorb enough solvent so that it will 25 vdition. While material of the Lovell type is soften quicker than material 'prepared' merely highly satisfactory in use, it sometimes gives rise by subjecting a fabric impregnated with a cellu- 1 to the diiculty that the colloidal matter becomes losic derivative dope to an air drying operation, so soft and mushy when the stiffener is dipped' e. g. that type of stiiener'known as lthe air 3o into. the solvent, that the colloidal matter canH dried colloided stiiener, Thus, the present 30 I leather shoe upper .will'be affected and softened terial. s

be forced through the `upper of a shoe of fabric method gives a material that overcomes the disor'similar material, during the lasting operaadvantages of ,the ordinary stiilening material tions, thereby staining, disguring, and ruining lwith precipitated colloidal matter, while retainthe upper; and similarly, the coating on a patent f ing. the` fundamental; advantages of such maduring the vlasting voperations so that the coat- Preferably, the` fabric to be impregnated is iming will be peeledv from the leather, thereby pregnated in a bath containing a precipitationdamaging the upper; and, again, in lasting shoes restraining agent that is immiscible or but parhaving cut-outs or perforations in the upper, tially miscible intvthe following bath in which 40 the colloidal matter may be forced through the the material is immersed for the purpose of pre- 40 j cut-outs or perforations, t cipitating the` colloidal material with which the I have now devised a method for .the manufabric is impregnated in the first bath. The'said facture of stifiening material of the" general agent may be either a 'solvent orl a non-solvent Lovell type which method provides a material for the colloidal material. `Whether the agent be i5- which, in itself,v overcomes the diflicultiesmena solvent or a non-solvent, its primary character-1 45 tionei istic is that it is immiscibleq or at most only par- In-the accompanying drawing, the-figure a tially miscible with the precipitating bath, as f highly 'conventional exaggerated .cross sectional otherwise there would be complete precipitation viewof stiflening material. made in accordance in'theprecipitating bath. When the impregnatwith the present procedure?" A, l o

. One object of 4,my -invention to Vprovide a are concerned, is composed of only a single ingremethod for the production of an improved stiidient, this ingredient must' not only be a restrainening material ofthe mentioned and otherv deingagent but must also be a solvent for the col- Silable(Y:hiti'ii.ei'ierlsiiics. T0 this end alldvvlso t0 u loidal material and -be but partially' miscible inv improve :generally 4on methods of' the general the precipitating bath. lWhen the impregnating 55 ing bath, so far. as the1iquid1ngredients'thereoi 50 bath comprises, as regards the liquid ingredients, more than one ingredient, the restraining agent need not be a solvent, provided one of the other ingredients present is a solvent; and, furthermore, this ingredient that is a solvent may be entirely miscible in the precipitating bath since the agent furnishes the factor of immiscibility called for. The precipitating liquid in the precipitating bath tends to immediately and oompletely displace the impregnating liquid to the extent that that liquid is miscible in the impregnating bath; but to the extent that that liquid is immiscible in the impregnating bath it restrains its own immediate or complete displacement, and thereby to that extent prevents the precipitation of a part of the colloidal matter.

For the production of goods in accordance with the invention, when the precipitating bath is water, there may be added to the impregnating bath, of say cellulose nitrate with ethyl alcohol and acetone as the solvent, a quantity of toluol since this is nearly immiscible in water: A sheet of the fabric, that it is desired to treat is passed through the colloidal solution, to thoroughly impregnate the fabric and then, without drying, it is passed into the precipitating bath Where the precipitating liquid tends to displace the solvent; the restraining agent prevents the immediate or complete displacement of the solvent and prevents the complete precipitation of the colloidal matter. When this operation is completed, and the material is removed from the bath and dried and as mentioned above, a portion of the colloidal matter will be found in a harder or more- Vcolloided form than the precipitated matter.

Withoutrestricting the invention thereto, the following will serve as specific examples thereof ,This stiffener may be made by thoroughly pregnating a piece of cotton flannel with` following colloidal solution:

imthe Cellulose nitrate lbs 300 Ethyl alcohol gals 145 Acetone do--- 15 Carbon tetrachloride do 30 The impregnated annel is then, without drying, passed to a precipitating bath of Water and immersed therein for 15 minutes, where the carbon tetrachloride, being nearly immiscible in water, will prevent the Water from completelyl displacing the alcohol and acetone and precipitating completely the cellulose nitrate. The material is then air dried. For carbontetrachloride may be substituted an equal quantity of toluol, the treatment being otherwise the same.

This stiffener may be made by thoroughlyimpregnating a sheet of fibrous material, such as felt, with the following colloidal solution:

Cellulose acetate lbs 300 Ethyl alcohol gals-- 80 Acetone do 80 Toluol do--- 30 III This stiffener may be made by thoroughly impregnating a sheet of absorbent paper with the following colloidal solution:

Ethyl cellulose -lbs 300 Ethyl alcohol gals 80 Acetone do 80 Naphtha do 30 The impregnated paper is then, without drying, passed to a precipitating bath of water and immersed therein for 15 minutes, where the naph- The particular collidal matter and the stiff-A ener kto which the present invention is applicable may be, as above indicated, of many general types. When of cellulosic derivative, it may be of cellulose ester, e. g. cellulose nitrate or cellulose acetate `or cellulose ether, e. g. ethyl cellulose or benzyl cellulose or any suitable combination thereof. Plastics made from these substances may be dissolved and used. `The solvent for treatment in particular accordance with the present invention will, of course, be selected for compatibility with the particular colloid in question.

Other examples of mixtures of liquids that might be used as solvents are alcohol or acetone or methyl ethyl ketone, etc., together withy one lor more of the following, ethyl acetate, cas- .tor oil, toluol, gasoline, butyl alcohol, carbon the precipitating bath, the times of immersion thereinfandsuch factors will, of course, be vav ried to meet the particular conditions as will be understood by those skilled in the art. 'Ihe above examples are given merely as illustrations as the percentages of the restraining agent in the impregnating bath may be varied tofmeet the particular conditions.

In any case, in consideration of'the result desired and as exemplified by the times stated in the above examples, the time ofv immersion in the precipitating bath is so correlatedwith the amount and efficacy of the particular restraining agent used that the restraining agent will, for the full length of the period of immersion in the precipitating bath, prevent the precipitation of more than a part only of the colloidal matter. As will be understood by those skilled vin the art, these factors may be widely varied to meet the circumstances o1' particular cases.

In the use of the fabric, blanks of suitable shape may be cut therefrom and, when dipped into suitable solvent in general accordance with Lovell, the colloidal matter is resolved into a coalescent, flaccid body which 4may be placed and conformed into the desired shape and will dry in the desired shape, stifl, flexible, and resilient.

While boots and shoes'have been more particularly referred to, it will be understood that stifleners of the present type may be used in any article of footwear where their use recommends itself, and furthermore, may be used at any particular location desired, as in the toe to form the box or in the heel to form the counter.

l. Method comprising impregnating a fabric throughout with a cellulose derivative solution, passing the fabric without drying into a precipitating bath, the solvent-liquid content of said solution and said precipitating bath being at least partially immiscible and the fabric being subjected to said precipitating bath `for a period of time only sufcient to precipitate part of the cellulose derivative, drying said impregnated fabric, and thereafter treating `said fabric with a cellulosey derivative solvent to soften it, shaping it, and allowing it to dry in the desired final form.

2. Method comprising impregnating a fabric throughout with a cellulose derivative solution,

said solution comprising a waterfsoluble solvent for the cellulose derivative and a water-immiscible liquid, passing the fabric without drying into a water bath, the fabric being subjected to said water bath for a period of time only suiiicient to precipitate part of the cellulose derivative, drying said impregnated fabric, and thereafter treating said fabricwith a cellulose 4derivative solvent to soften it, shaping it, and allowing it to dry in the desired final form.

3. Method comprisingimpregnating a fabric throughout with a I cellulose nitrate solution, passing the fabric without drying into -a precipitatingy bath, thev solvent-liquid content of said solution and said precipitating bath being at least ypartially immiscible and the fabric being subjected to said precipitating bath for a period of time only sumcient to precipitate part of the cellulose nitrate, drying said impregnated fabric,.and thereafter treating said fabric 'with a cellulose nitratesolvent to soften it, shaping it,

and allowing it to dry in the desired final form. 4. Method comprising impregnating a fabric V throughout with a cellulose nitrate solution, said solution comprising a water-soluble solvent for the cellulose nitrate and a water-immiscible liquid, passing the fabric without` drying into a water bath, the fabric beingl subjected to said 5. Method comprising impregnating a fabric throughout with a cellulose nitrate solution, said solution comprising a water-soluble solvent for the cellulose nitrate anda Water-immiscible liquid from the group consisting of carbon tetrachloride and toluol, passing the fabric without drying into a water bath, the fabricv being subject to said water bath fora period of time only sufficient to precipitate part of the cellulose nitrate, drying said impregnated fabric, and thereafter treating said fabric with a cellulose nitrate solvent to soften it, shaping it, and allowing it to dry in' the desired final form.

6. Method comprising impregnating a fabric throughout with a cellulose acetate solution, vsaid solution comprising a water-soluble solvent for the cellulose acetate and a waterl-immiscible liquid, passing the fabric Without drying into a water bath, the fabric being subjected to said water bath for a period of time only sufficient to precipitate part of the cellulose acetate, drying said impregnated fabric, and thereafter treating said fabric with a cellulose acetate solvent -to soften it, shaping it, and allowing it to dry in the desired final form.

7. Method comprising impregnating a fabric throughout with a cellulose ether solution, said solution comprising a water-soluble solvent for the cellulose ether 'and a Water-imrniscible liquid, passing the fabric without drying into a Water bath, the fabric being subjected to said water bath for a period of time only suicient to precipitate part of the cellulose ether, drying said impregnated fabric, and thereafter treating said fabrbic with a celluloseether solvent to soften it, shaping it, and allowing it to dry in the desired final form.;

8. Method comprising impregnating a fabric throughout with an ethyl cellulose solution, said solution comprising a water-soluble solvent for the ethyl cellulose and a Water-imrniscible liquid, passing the fabric without drying into a water' bath, the fabric being subjected to said water bath for a period of time only sufficient to precipitate part of the ethyl cellulose, drying said impregnated fabric, and thereafter treating said fabric with an ethyl cellulose solvent to the desired final form.

RUSSELL HAMILTON. 

